Residential customers pay a flat annual sewer service charge per dwelling unit. Each residential customer class pays the same sewer rate because it is based on the average wastewater from a typical home and the cost of providing sewer service.

There are four flat rate residential customer classes:

1) Single-Family Homes,

 2) Multi-Family Residential,

3) Mobile Homes and Recreational Vehicles, and

4) Accessory Dwelling Units (ADUs).

A flat sewer rate helps keep customer bills predictable and stable. The rate is established through a cost-of-service analysis and adopted in accordance with Proposition 218 requirements.

Residential sewer charges are collected through the County property tax roll and appear as a separate line item on the annual property tax bill.

Wastewater use is not individually measured for homes, and residential sewer use is generally consistent and predictable. Because of this, a flat annual rate is commonly used and is the industry standard. This approach also follows California Proposition 218 requirements.

Sewer charges are collected through the property tax roll to reduce administrative costs and ensures consistent, timely payment. This method is commonly used among California wastewater agencies and helps keep rates lower.

On your property tax bill, the charge appears as a separate line labeled “ISD Sewer Use Fee.”

If you are a renter, you do not receive a separate sewer bill. The property owner pays the sewer charge, and it is included in their annual property tax bill.

Commercial customers pay two types of charges:

•        A fixed customer charge

•        A variable charge based on either water use (metered customers) or building size (non‑metered customers)

This sewer rate structure helps ensure customers pay based on how much they use the wastewater system.

ISD is a not-for-profit government agency. We are fiscally governed by the legal Proposition 218 guidelines for our annual cost of service rates. This does not allow for any discounts, or the ability for one customer to subsidize another customer when covering the cost of the wastewater services we provide them.

Some businesses produce stronger wastewater than a typical home. This wastewater can require more energy, chemicals, and treatment to process.

ISD uses low-, medium-, and high-strength commercial categories, so businesses pay based on the cost of treating their wastewater. This helps ensure each customer paya a fair share of the costs.